Antibackflow and antisiphonage valve



Nov. 20, w45. F. CARLTON ANTIBACKFLOW AND ANTISIPHONAGE VALVE Filed Sept. 26, 1941 2 Sheets-Sheet l New. 20, 1945. F. CARLTON ANTIBACKFLOW AND ANTISIPHONAGE VALVE 2 Sheets-Sheet 2 Filed Sept. 26. 1941 Patented Nov. 20, 1945 UNITED STATES PATENT OFFICE ANTIBACK'FLOW AND ANTISIPHONAGE VALVE Frank Carlton, Los Angeles, Galli. Application September 28, 1941, Serial No. 412,372 1a claims. l(ci. 217-1) 'I'his invention relates to liquid ilow systems and particularly pertains to an anti-backnow and anti-siphonage valve.

In connection with liquid ow systems, such for example as those in which water is delivered from a water main through a connecting service pipe to the domestic lines of a building, or in cases where Water is delivered in the same manner to equipment in an industrial plant or to any private or domestic piping system or xtures or equipment thereon, occasions sometimes arise when the waterpressure in the supply line and the water pressure in the domestic piping system become unbalanced so that a major pressure occurs in the domestic piping system. Under such conditions a backflow action will be created flowlng reversely from the domestic service lines to the supply line with the result that this water, now considered used as well as polluted, contaminated, or containing deleterious matter, may be drawn into the domestic piping system, through the service line and into the water mains, and thus contaminate the pure water supply. Heretofore, various structures have been produced in an attempt to interrupt the backow, and thus the back-siphonage of water vfrom the domestic service line into the supply line, or to interrupt or prevent back-Siphonage from water served fixtures, devices, containers, receptacles or equipment into the domestic piping system, or to interrupt and make impossible backflow communication between dualinterconnected supplysystems at points of cross-connection where said systems contain water from diierent sources or where one supply system, often called the secondary, is not under proper sanitary supervision. These have in certain instances proved objectionable due to the fact that a leakage at or through the structure or device of the back owing water can occur without detection. This might be brought about by the failure of valves to seat, or by the fact that certain parts might become damaged or barrier walls ruptured within the valve structure itself. It is the principal object of the present invention, therefore, to provide automatic means which will act to interrupt the backilow and back-siphonage of water from the domestic service lines to the supply line or between Water served fixtures, devices, containers, receptacles or equipment and the domestic or supply piping system;

desired points therein at a time when either a back-siphonage or backilow condition exists, whereby a reverse ilow of water will be interrupted by said chamber and be expelled to at -mosphere, and thus have no opportunity to reach or enter any part or parts of the piping system that said device has been interposed to prevent.

It is another object of the present invention to so construct certain vital parts, whose purpose is to impose a moving water-tight barrier between iluids having either variable pressure difierentials or being static br non-moving, whereby a rupture or leakage of any of said barrier parts will be discernible on the outside of the valve housing, thus indicating need of repair or replacement of parts, and so providing for the rst time in a device ofk this sort a constant externally visible alarm against breakage or functional failure of internally operating mechanisms or parts.

The present invention contemplates the provision of a valve structure having a main housing, an induction passageway connected to a supply line, an eduction passageway connected to a service line, an interposed chamber through which said passageways may communicate and which chamber may be opened directly to atmosphere while creating an air chamber completely severing all iiuid communication between the induction and eduction passageways, the structure including valves responsive in diilerent ways so that when a backilow condition .is approached there will be created an interposed air chamberv between said induction and eduction passageways.

In this specication the terms supply line and service line are used. It is to be understood that these terms apply to any induction and eduction connections.

The invention is illustrated by way of example in the accompanying drawings in which:

Figure 1 is a view in central vertical section through one form of the invention with the parts in the relationship which will exist when the fluid flow is normally passing from the supply main, through the 'connecting service line, through the device, and into the private piping system for which it is intended.

Fig. 2 is a view in central vertical section similar to'Fig. l showing the relation of parts of the device when a backow condition exists.

Fig. 3 is a fragmentary view in section and elevation showing a means of utilizing a sealed unit filled with oil or the like, transmitting pressure differentials between the supply line and the proper part of thevalve chamber.

2,sso,412

lower end to a ilange 92 of the nut 53. Th'e bellows Il is disposed within the bellowsil and in spaced relation thereto to form an annular space ll.

lows 90 and the bellows 6I are secured to a closure disc M. The iiange 62 of the nut 53 and a corresponding ilange 69 of the spacer 5I are formed with passageways 63 which establish communication between the space 63 and the space 42. It will thus be seen that a compound bellows and diaphragm structure is provided which', if ruptured, would cause a leakage of liquid through the ducts B9 to the atmosphere. This would visually indicate a failure of the structure within the valve.

Carried by the disc is a tappet stem 91 which is rigid with the disc 99 and extends downwardly through a central opening 6B in the guide and clamping member 98. The lower end of the tappet 91 carries a sleeve 69 into which the stem 10 of the relief valve 29 extends. The tappet rod 61 is intended to strike against the upper end of the stem 19 and to move the valve 2li away from its seat 25. An adjusting screw Il is threaded into the end of rod 61 to compensate for variable lengths of the bellows 22, 69 and 6 I.l

The supply line conduit I2 is tted with a check valve 12 through' which the water flows into the valve housing I0. The valve 12 is mounted on the inflow side of the chamber member I9. Any other type of valve may be used. 'I'he check valve 12 is spring or weight loaded in order to create a pressure differential to thus cause water owing into chamber i9 to bypass through a tube 15 to interior of bellows 22 thereby closing bleeder valve 2i in preparation for the normal ow of water through the structure.

Mounted within the service line conduit I 4 at a point beyond the housing I 9 is a check valve 19. This valve 16 will obstruct th'e backiiow of water from the service line I9 into the valve housing when closed. At a. point on the service line side oi the valve 16 is a tube 19 which establishes communication between the conduit Id and the chamber 89 which occurs in the portion 56 of the housing cover 55, and within which chamber the Sylphon bellows 60 and 6I are positioned. Attention is directed to the fact that the tubes and I9 are both unobstructed, the first named tube being in constant communication with' the supply conduit I2 and the last named tube being .in constant communication with the service conduit I9. It is also to be noted that the tube 19 is of relatively large diameter to permit unrestricted iiow of liquid from the service line I4 to the chamber 39 when the valve 16 is closed due 4to back pressure in the service lines or a static pressure throughout the device.

Referring to Fig. 3 of the drawings, it will be seen that the tube 15 has been modified in its construction so that there will not be any passage 'of water from the supply line I2 to the conduit 29, thus insuring the tube 15 will not become clogged. Mounted within the chamber 8i is a Sylphon bellows 82 directly connected with the` tube 15. The Sylphon bellows, the tube 15, the conduit 29 and the Sylphon bellows 22 are all .nlled with an incompressible fluid, such for ex- 'I'he lower end of the bellows'i is secured to the nut 53. The upper ends of both the belphragms 39 and I0, at which time they are h'eld preferably in closer relation to each other than shown in Figs. 1 and 2. In order to space the diaphragm so that th'ey will move in unison when flexed, a plurality of balls 95 are placed between the diaphragms 39 and 40. 'Ihese balls may be steel or rubber balls, such as are used in antifriction bearings, and are of a diameter agreeing with the space between the diaphragms. If desired, an intermediate rubber web may be used. By this arrangement it will be seen that the dlaphragms will be held in spaced relation to each other while they ilex, and at the same time fluid may pass between and around the balls 95 so that a leak may be indicated. Attention is also directed to the fact that the size and number of balls may be selected to impose a desired .weight upon the diaphragm 39 and to thus tend to urge the valve disc 50 onto its seat 31. The advantage resulting from thus weighting or loading the valve 5I) is found when the pressure within the chamber member Il) is insumcient to provide the desired pressure reduction. The weight thus provided will maintain the valve 50 seated until the induction pressure rises sumciently to again open the said valve 59. This insures even under very low pressure conditions that th'e valve 59 wil1 seat to prevent backflow and to permit the operation of the relief valve as hereinafter set forth. 'I'he use of the balls 95 for spacing elements will also insure that the diaphragms 39 and B0 may flex throughout th'eir free area with out restriction from spacing means such as the webs M. This will cause free and uniform movement to take place under the influence of fluid pressure exerted against the diaphragms.

In operation of the present invention water is delivered through the supply pipe I2. For tli'e purpose of this description it will be assumed that the normal pressure of water in the supply line is 5U pounds gauge pressure. As the water flows through the conduit I2 into the passageway 32 of the housing I0 it will force the check valve 12 open. At the same time the pressure exerted by the water in the supply line will act through the tube 'I5 and the conduit 29 to fill the Sylphon bellows 22 and exert a pressure on the disc 23, tending to force the relief valve 29 upwardly against its seat 25 and'th'us prevent the discharge of water from chamber 34 through the valve seat 25 and into the chamber 83 of the cylinder I9. The water which -is delivered through th'e supply pipe I2 will act against the under face'of the diaphragm 39 and will force this diaphragm upwardly while lifting the valve disc 50 from the valve seat 31. The water may then pass into the chamber 34 through the central opening in the valve seat 3'I and may then ow through the passageway 33 into the service conduit I4. When the service line I 4 is filled the tube 19 will also be filled. Water from this tube will flow into the chamber around the Sylphon bellows 60 and will exert a pressure against this bellows and tli'e top of closure plug 66 .as well as against the upper face of the diaphragm 40. As previously mentioned, the diaphragms 39 and 40 have been designed to have diierential pressure areas so that` a regulator vaction will be provided whereby the main ilow *valve automatically moves toward a closing position to establish a predetermined reduction in pressure between the induction pressure and theeduction pressure, or-moves lto a closed position and shuts off normal flow between the induction and eduction lines when ,the eduction pressure rises to a predetermined amount below the induction pressure.

Attention is directed to the fact that the gauge pressure occurring between the diaphragme 39 and 40 and between the walls of the Sylphon bellows 80 and 6I under normal conditions stands at zero, since the spaces 42 and 63 are in constant communication with the atmosphere. It will therefore be evident that in event either th'e diaphragm 39 or 40 leaks, or the Sylphon bellows SII or 6I leaks, that this leakage water will flow out through the passageway 59 and give visual indication of structural failure of the apparatus.

An important and vital result achieved by the dual bellows 60 and 6I and the parallel diaphragms 39 and 40 aside from the visual evidence of leakage, which is obtained, as compared with a device including a single bellows and diaphragm, is that in the latter event direct communication would be established through the device, whereby contaminated or polluted water would flow into the supply stream. This flow would be established through the tube I9 to the chamber B0, th'en through the ruptured diaphragm or bellows into the valve housing, and then into the supply pipe I2. It will be evident that nothing of this kind can take place'with the dual construction.

In the operation of th'e device here described, it is desirable to maintain a predetermined lesser pressure in the eduction line I4 than in the induction line I2. This is desirable in order to insure that the bleeder valve 24 will remain closed during normal flow but will be opened before a superior pressure exists in the eduction line. 'I'his is accomplished by operation of the main valve, which functions as a differential pressure regulator, since it is moved by diaphragms 39 and 40. These diaphragms have different pressure areas, the larger being exposed to eduction pressure.

When water is no longer withdrawn from the eduction line I4, the eduction pressure will consequently rise. This increase in eduction pressure will then be imposed through tube 'I9 upon the larger area presented by the upper face of the diaphragm 40. This will cause the main valve to close while the pressure on the eduction line is still a predetermined amount below the pressure then existing in th'e induction line.

It will be understood that on the discharge side of the main valve 50 is the bleeder valve 24, which opens under a backfiow condition and relieves the pressure in the outlet chamber 34 by discharging such' quantity of water through the valve 24 from the eduction side of the system as is necessary to prevent the pressure in the chamber 34 from rising above the induction pressure. This bleeder valve 24 is responsive to service line pressure on one side and to an opposing combination of eduction pressures exerted through tube 'I9 and chamber 80, and also exerted by the fluid in pressure ch'amber 34 against the bleeder valve disc 24. Under normal conditions, or when normal flow ceases, the bleeder valve 24 remains in a closed position. However, the effective areas of the bleeder valve structure exposed to the opposing pressures of eduction and induction :fluids are so proportioned that if the induction pressure falls or the eduction pressure rises until a backflow condi-tion is approached, the bleeder valve 24 opens suniciently to reduce the pressure in the outlet chamber. If the eduction pressure continues to rise, the pressure in the outlet chamber 34 will continue to fall, and nally will reach zero when the eduction pressure has become equal to the induction pressure. Consequently, the pressure in the outlet chamber 34 will then be at zero. If th'e eduction pressure should rise above that of the induction pressure, this same condition would exist.

Attention is directed to the fact that in the event check valve 'I6 leaks while the valve 24 is opened the leakage would drain through valve seat 25.

When the fluid pressure in the supply line I2 is restored and becomes sumciently greater than that in the service line I4 and the chamber 34 the check valve I2 will move to an open position and will allow the liquid to pass into the valve housing I0 and to act against the lower face of the diaphragm 39. At the same time the pres'- sure of the liquid within the supply line I2 will be transmitted through the tube I5 to the Sylphon bellows 22 and will force the relief valve 24 upwardly onto its seat. Attention is directed to the fact that since the valve 12 is either spring or weight loaded there will be a tendency for it to remain seated while an advance ilow of fluid passes through the tube 15 and the duct 29 to the Sylphon bellows 22. This will insure that the valve 24 is seated in advance of the time the water from the supply line reaches it. Thus there will not be a tendency for wastage of water before the valve 24 closes. When the valve 24 closes, a flow conduit will be established through the valve housing I0 and the passageway 33 to the service line i4. The check valve 1B will then be opened so that the pressure throughout the system will be restored to a normal operating condition.

It will thus be seen that by the arrangement here disclosed a structure is provided which may be interposed between a fluid supply line and a service line of any character, and which will act automatically when a backflow condition exists to establish a complete air gap between the twolines while permitting any water leaking from the service line side to drain to atmosphere. It is also to be noted that due to the structural arrangement of the-parts of the valve the leakage of any of the valve diaphragms or bellows will be indicated directly irrespective of the flow condition in the lines and the pressure values of the liquid in the service line and the supply line.

While I have shown the preferred method of preventing backow and back-siphonage of fluid from a domestic service line to a supply line and apparatus for carrying out the method, it will be understood that various changes may be made in the steps of the method and the combination, construction and arrangement of parts of the apparatus by those skilled in the art without departing from the spirit of the invention as claimed.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

l. An anti-backow device adapted to be interposed between an induction line and an eduction line within both of which variable uid pressure prevails, an intermediate partition in said device having a valve opening therethrough and through which fluid may iiow from the induction line to the eduction line, a main valve element for closing said opening, a check valve in the eduction line opening in the direction of normal flow. fluid pressure responsive means associated with the main valve for moving the same, the induction iiuid pressure acting thereon to open the main valve. and a conduit connecting with the eduction line at a point beyond the cheek valve and delivering eduction duid to the fluid pressure responsive means to exert a pressure opposing that of the induction fluid and acting to urge the main valve toward a closed position, the fluid pressure responsive means including dilerential pressure responsive areas acted upon by the induction and eduction fluids, whereby the main valve will close when the eduction pressure rises to a predetermined amount below the induction pressure.

2. A valve structure of the character described, comprising a valve housing having a fluid passageway therethrough, a partition in said passageway, a valve opening through said partition, a movable partition valve element for closing said opening, an induction passageway at one side of said partition, an eduction passageway at the opposite side of said partition, a check valve disposed in the eduction passageway and opening in the direction of ilow of fluid from the induction passageway to the eduction passageway, an opening in the wall oi' the valve housing on the eduction side of the partition and between the partition valve and the eduction check valve, a relief valve for closing said opening, a fluid pressure responsive element acted upon by induction fluid from in advance of the partition valve tending to maintain the partition valve open, uid responsive means responsive to fluid pressure derived from the induction fluid line in advance of the partition valve tending to maintain the relief valve closed, fluid responsive means deriving pressure from the iiuid beyond the check valve in the eduction line tending to maintain the partition valve closed, and fluid responsive means derived from pressure of fluid in the eduction line tending to maintain the relief valve open, the pressure areas of the responsive means exposed to eduction pressures being greater than the pressure areas exposed to induction pressures.

3. An anti-backflow device adapted to be interposed between an induction line and an eduction line within both of which lines variable fluid pressures prevail, an intermediate partition within said device having a valve opening therethrough and through which fluid may flow from the induction line to the eduction line, a main valve element for closing said opening, a check valve in the eduction line opening in the direction of normal ow, an outlet to atmosphere in the eduction line at a point between the main valve and the check valve, a bleeder valve normally closing the outlet, uid pressure responsive means including separate fluid pressure elements associated with the main valve and the bleeder valve and acting to open and close said valves independently of each other, the said fluid pressure responsive elements presenting differential fluid pressure responsive areas, the greater of which areas is subjected to the eduction pressure tending to close the main valve whenever the eduction pressure approaches the induction pressure and providing differential areas acting to actuate the bleeder valve, the said differential areas being so proportioned as to actuate the relief valve to open position after the main valve closes and before the eduction pressure equals the induction pressure, a conduit connecting with the eduction line at .a point beyond its check valve and delivering fluid pressure to the uid pressure responsive means of the main valve and the bleeder valve acting to urge the main valve toward a closed position and the bleeder valve toward an open position. l

4. The structure as defined in claim 3 wherein the fluid pressure responsive means for the main valve includes two opposed fluid pressure responsive elements and the uicl pressure responsive means for Athe bleeder valve includes two fluid pressure responsive elements.

5. An anti-backiow device adaptedto be interposed between an induction line and an eduction line within both of which variable fluid pressures prevail, an intermediate partition within said device having a valve opening therethrough and through which fluid may flow from the induction line to the eduction line, a main valve element for closing said opening. a check valve in the eduction line opening inthe direction of l normal flow, an outlet to atmosphere in the eduction line at a point between the main valve and the check valve, a bleeder valve normally closing the outlet, fluid pressure responsive means for the main valve and fluid pressure responsive means for the bleeder valve, a conduit connecting with the eduction line at a point beyond its check valve and delivering eduction fluid to the fluidv pressure responsive means of the main valve and the bleeder valve acting to urge the main valve toward a closed position and the bleeder valve toward an open position, the uid pressure responsive means of the main valve and the uid pressure responsive means of the bleeder valve comprising elements so proportioned that the main Valve closes when the eduction pressure rises to a predetermined amount below the lnduction pressure and the bleeder valve opens after the main valve closes and before the eduction pressure equals the induction pressure.

6. A backflow prevention device for use in a uid distributing system having an induction and an eduction line through which iuid ows under pressure, means for producing and maintaining during normal flow a substantial pressure drop between induction and eduction pressures, a vent valve, means for actuating said valve including biasing means for said valve comprising pressure responsive means subject to the induction and eduction pressures and so constructed and arranged that when the induction and eduction pressures are equal, said pressure responsive means is biased in an opening direction. and when the normal pressure drop is maintained, said bias is overcome by the pressure differential acting on said pressure responsive means and the valve is maintained closed, whereby the vent valve will operate to vent the device between the induction and eduction lines when the eduction pressure is less than the induction pressure by an amount less than the pressure drop.

7. A backow prevention device for use in a water distributing system having an induction and an eduction line through which iluid flows under pressure, pressure responsive means for producing and maintaining during normal flow a substantial pressure drop between induction and eduction pressures, a vent valve, means operatively connected between the induction and eduction lines including biasing means for said valve comprising pressure responsive means subject to the induction and eduction pressures and so constructed and arranged that when the induction and eduction pressures are equal said valve is biased in an opening direction and when the normal pressure drop is maintained, said bias is overcome by the pressure differential acting upon the pressure responsive means and the valve is maintained closed whereby the vent valve will operate to drain the device between the induction and eduction lines when the eduction pressure is less than the induction pressure by an amount less than the pressure drop.

8. In a device for preventing backilow in a water distributing system from an induction line to an eduction line, the combination of a valve member opening in the direction of water now from the induction line to the eduction line, said valve member including means for producing and maintaining during normal flow a substantial pressure drop between the induction line pressure and -the eduction line pressure to form a reduced pressure zone, a valve for venting the zone to the atmosphere, said vent valve including biasing means comprising pressure responsive means subject to the induction and eduction pressures and so constructed and arranged that when the induction and eduction pressures are equal, said valve is biased in an opening direction, and

when the normal pressure drop is maintained,

said bias is overcome by the pressure differential acting on said pressure responsive means and the 'valve is maintained closed.

9. In a backfiow prevention device for a water distributing system having an induction line and an eduction line, a flow valve between the lines, means subject to induction and eduction pressures upon opposite sides of the ilow valve for producing a diierential and substantial pressure drop during normal flow and at cessation of normal flow, a vent valve, biasing means for the vent valve, including means subject to induction and eduction pressures and so constructed and arranged that said vent valve is biased in a closing direction during normal iiow and at cessation of normal ow, and is biased in an opening direction when the eduction pressure is less than the induction pressure by an amount less than the pressure drop determined by thev rst stated means.

subjecttoinduetionandeductionlinepressuxs. lLThecombinat-ionofclnhnmwhichthe meansprovidingfortbepnssuredropsprlng 12. Incombinationina'aterdlstributimmtem having an induction line and an line, of a chamber member between the said lines. means for providing a sumantial pressure drop in the chamber member, a vent valve, means subject to both induction and eduction pressures for holding said vent valve in closed position when thepressuredropintheebnmberism and operating upon the change of pressure infiuencethereontoopensaidventvalvewhm the eduction pressure is las than the inductim premure by an amount less'tlmnthe pressure drop.

llnabackilowpreventiondevicathecombination of a chamber device, an induction line leading to the chamber device, an eduction line leading from the chamber device where water normally ows from the induction line through the chamber device and out the eduction line. means operative during normal w and at csation of normal flow to produce a substantial pressure drop between the induction and educ- 10. 'I'he combination defined in claim 7 wherein closed.

the pressure responsive means for producing the pressure drop comprises a differential area valve 40 FRANK CARLTON. 

